Known single layer transfer (SLT) processes can be modified to improve the performance of RF switch and PA processes within SOI technology. On SOI technology, PA performance is limited by self-heating. A thinner rather than a thicker buried oxide (BOX) layer is better for power dissipation. The placement of a thick metal layer directly under the BOX layer may also improve heat dissipation. However, an RF switch benefits from a thicker rather than a thinner BOX layer to achieve a better off-capacitance/BOX capacitance (Coff/CBOX) ratio.
A need therefore exists for methodology enabling selective thinning of the BOX layer and deposition of a thick metal layer in the PA power cell region without reducing the Coff/CBOX ratio of the RF switch and the resulting device.